Homestead mailing list

["Lynda" <lurine AT softcom.net>]

The fact is that IPM works.  IPM creates jobs.  Of course, there aren't big
bucks in IPM for the big $$ companies.  Here's the other side of the
argument over DDT:

DDT A PANACEA FOR WEST NILE?

THANK GOODNESS HEALTH AUTHORITIES HAVE MORE SENSE

Jim Bull

Detroit News columnist Thomas Bray laments that DDT is not being considered
for use in the fight to control the spread of West Nile virus (Still in
Denial about West Nile, 5-18-03). Bray asserts that DDT would be the most
effective weapon to use to combat West Nile. He quotes an EPA hearing
examiner as saying that DDT is safe, not carcinogenic, not mutagenic, nor
teratogenic to humans. He goes on to report that the same examiner stated
that DDT does not harm wildlife if used properly. On that basis he concludes
that the ban on use of DDT is unwarranted and has doomed people, especially
children, to die from malaria.

Although DDT may not alter the genetic structure of an organism, it
certainly has plenty of toxic effects. The US EPA "Persistent
Bioaccumulative and Toxic Chemical Program" reports that DDT is a probable
human carcinogen, damages the liver, can cause liver cancer, temporarily
damages the nervous system, reduces reproductive success, and damages the
reproductive system. In Israel, breast cancer rates decreased dramatically
after DDT was banned from use on dairy farms. One reason DDT effects the
reproductive success of organisms is that it is an endocrine disruptor which
mimics estrogen. This can result in lower fertility in human males. In some
species of fish it can even change their gender. It certainly can disrupt
courtship and may make mating impossible in many species.

Because of DDT's affinity for fat, it is readily excreted in cow and human
milk, which is why the ban in Israel had such a dramatic effect. Since DDT
resists being metabolized, it is stored in the fatty tissue of animals and
accumulates over time. This effect is compounded in predators that eat lots
of prey species with DDT present in their bodies. While DDT can outright
kill some fish that have eaten too many insects laden with it, other fish
live to pass on their accumulation to predators, including humans. Although
it was banned in 1972, over thirty years later there are still fish
consumption advisories for DDT in the Great Lakes and many other watersheds.

In predatory birds, DDT did its damage in another way--it prevented
sufficient production of calcium carbonate in the eggshell making process.
The result was eggshells so thin that they broke when the adult female
attempted to incubate them, thus many fewer young were hatched. The Bald
Eagle, the Peregrine Falcon and many other birds were on the brink of
extinction until DDT was banned. Banning DDT saved our national symbol.

And not just large birds were affected. Many insect and worm-eating birds
succumbed to the effects of DDT's bioaccumulation. As a child growing up in
the 1960s, I remember seeing American Robins convulsing in severe DDT
tremors before they died. We sent more than one carcass to ornithologist
Walter P. Nickell (and one time DAS president) at the Cranbrook Institute of
Science so he could forward them to Michigan State University for analysis.
It was not a pretty sight to see. Nickell and George Wallace at M.S.U.
supplied this kind of data to Rachel Carson as she researched her book,
Silent Spring.

A few other traits of DDT should cause concern. It takes fifteen years or
more to break down in the environment (which is why we still have fish
advisories warning about DDT) and it can be absorbed by some plants, which
means that a vegetarian diet will not save you from its toxic effects.

Maybe a certain amount of DDT can be consumed without killing the organism,
but this does not mean the substance has "no deleterious effects on wildlife
if used properly." There is no way to use DDT that will prevent
bioaccumulation, persistence in the environment or absorption by plants.
Delayed toxic effects are still toxic nonetheless.

Would DDT have prevented the spread of malaria and would it be the best tool
to use to combat West Nile? Probably not. There is one other fact about DDT
and most other pesticides that needs to be told: insects develop resistance
to pesticides. The few insects that do not succumb to the pesticide survive
to reproduce and spread their genetic resistance. In 1997, the National
Research Council reported 4,000 examples of resistance to pesticides in 500
species of insects. In many cases the resistant insect population grows to
levels that surpass what they were when spaying began. Before DDT was
banned, this resistance was already becoming evident.

What should we do? Precisely what most health organizations and communities
are doing, using Integrated Pest Management (IPM). In IPM the ecology of the
insect is studied, and a variety of measures are taken to control the
infestation based on that information. A chemical or biological pesticide is
used only as a last resort, and then only if it can be shown to be effective
and that the benefits outweigh the risks.

While we are justifiably concerned about West Nile, its human victims and
the sporadic mortality of crows and other birds, it is not a serious health
threat for most people. Birds are the primary hosts, not humans. Less than 1
in 150 people bitten by infected mosquitoes get any symptoms of the disease,
and most of those do not develop the brain infection known as encephalitis.
No more than 10% of those who develop encephalitis die and most of those
cases have been elderly people whose other health problems make them more
susceptible. Flu, asthma and respiratory diseases each kill more people per
day than the total number killed by West Nile in the two worst months of the
"epidemic." West Nile is scary because it is new to us. We need to have a
healthy respect for it, but not the panic fomented by sensational media
reports. A sense of perspective is important when dealing with any serious
problem.

Eliminating habitat for larval mosquitoes in back yards, including old
tires, pet water bowls, and other containers with still water will make it
impossible for mosquitoes to complete their metamorphosis to biting adults.
Using mosquito repellents, wearing long sleeve shirts and long pants, and
reducing activities at dawn or dusk when mosquitoes are most active have
been shown to significantly reduce mosquito bites.. Spraying pesticides, on
the other hand, reduces the adult mosquito population only temporarily, as
populations recover quickly and pesticide resistance emerges. Studies have
shown that spraying distracts the public, lulls them into a sense of safety
and deters them from implementing the very factors that could prevent
mosquito contact in the first place. And, what Bray did not mention is that
DDT and other pesticides do not differentiate between good insects and
pests. Monarch butterflies and the economically important honeybee could be
affected as well. If pesticides are to be used in some cases, after other
IPM methods have been tried, the larvicidal bacteria that come in pellet
form are the best choice. Even that biological control method may have some
risks, despite claims that it is safe and is specific to only mosquitoes.
Nobody knows for sure that this bacterium will not infect beneficial insects
or other organisms. But it is far safer than chemical pesticides. And of the
chemical pesticides, DDT would be one of the worst to consider. Thank
goodness it is no longer an option in this country.

There is also a problem with Bray's assertion that the ban on DDT is to
blame for the continued high rates of malaria worldwide--most of the
developing world still uses DDT, and much of it is imported from U.S.
manufacturers. IPM is not only safer, it is the most effective approach to
combating insect or any other pests, animal or plant. Maybe if the countries
that continue to rely so heavily on DDT tried IPM, the numbers of malaria
victims would finally start to decrease.

----- Original Message -----
From: Gene GeRue <genegerue AT ruralize.com>
To: <homestead AT lists.ibiblio.org>
Sent: Saturday, January 08, 2005 8:49 AM
Subject: [Homestead] Rethinking DDT--or should we?


> This is a sobering article. Along with others we have recently read, it
> points out that malaria kills many times more people than the recent
> tsunami did. But--somebody give me a reality check, please--I find myself
> wondering if such human catastrophes are not simply Nature protecting
> herself, a way that Gaia is creating a balance from the increasing
> destructiveness of its dominant species. I feel pretty certain that human
> overpopulation is the biggest threat to our planetary home. Yet, not one
of
> us  could look a sick child in the face and not want to help in any way
> possible. But looking at the big picture, consider the outcome if all
lives
> were saved. Am I losing my humanity?